Synthesis and crystal structures of two new uranyl coordination compounds obtained in aqueous solutions of 1-butyl-2,3-dimethylimidazolium chloride
Two new uranyl coordination compounds, [C9H17N2]3[(UO2)2(CrO4)2Cl2(H2O)2]Cl·5H2O (1) and (C9H17N2)[(UO2)(C2O4)Cl] (2), have been synthesized by adding potassium dichromate (K2Cr2O7) or oxalic acid dihydrate (H2C2O4·2H2O) solution into an aqueous solution of uranyl nitrate and 1-butyl-2,3-dimethylimidazolium chloride [Bmmim]Cl. [Bmmim]Cl provides the charge balance and Cl ions that coordinate with uranyl ions. The fundamental building units of 1 and 2 are UO6Cl pentagonal bipyramidal structures. Compound 1 exhibits a graphene-like structure with a system molar ratio of 1:1 for U:Cr and crystallizes in the orthorhombic space group Pbca, with a = 25.644(3) Å, b = 12.996(14) Å and c = 29.198(4) Å. 16-Membered rings are formed by CrO42− and UO22+ in the crystal structure of 1. Compound 2 crystallizes in monoclinic space group P21/n, with a = 10.759(3) Å, b = 11.395(3) Å, c = 14.149(4) Å, β = 102.962(9)° and shows one-dimensional (1D) serrated chains. Within the crystal structures of 1 and 2, C–H[Bmmim]Cl⋯O hydrogen bonds are identified. O–Hwater⋯Cl hydrogen bonds are also detected in the crystal structure for 1.
